The present invention refers to a method for automatically assigning addresses in a bus system with a single or multiple wire bus, a plurality of participating units (referred to as units in the following) connected to the bus and a control device for issuing control signals to the units, the control device also being coupled to the bus, where each unit comprises an actuator and an actuator driving device for displacing the actuator along a displacement path defined by two end positions.
In order to minimize wiring efforts in automotive vehicles, for example, control signals for controlling actuators are more and more frequently sent via a bus to which, besides a control device, also the controlling devices for the actuator driving devices of the individual units are coupled. The actuator driving devices of a vehicle air conditioning, window lifters or the front seats, for example, are comprised in a bus system. To enable the control device to selectively control one or a plurality of actuator drives, addresses are assigned to these. At present, the addresses of units are stored by programming. While this procedure is relatively unproblematic during the assembly of a vehicle, the efforts required are all the greater if the entire unit, i.e. the actuator driving device including the control, has to be replaced in a garage, for example, since the garage has to be equipped with a corresponding programming device.
It is the object of the present invention to simplify the assigning of addresses in a bus system with a control device and a plurality of units with actuator driving devices and the necessary controlling devices.
The object is solved by the present invention with a method for a system of the kind mentioned above, the method comprising the following steps:
storing, in the control device, operating data sets that, upon adjustment of the actuators from one end position to another end position, describe expected operation parameters of the actuator driving devices of the units, these set parameters being different for each actuator driving device, and storing address data that are also different and are assigned to the different set parameters,
wherein the control device causes the actuator driving devices of the units to move the respective assigned actuators to the one end position,
wherein the control device then causes the actuator driving devices of the units to move the respective assigned actuators to the other end position,
determining the actual operating parameters of the actuator driving devices during the movement of the actuators of the units from one end position to the other end position,
wherein the control device issues the set parameters and the respective assigned address data to all units,
wherein each unit compares the actual operating parameters to the set operating parameters provided by the control device and accepts those address data as its address in the bus system, which belong to those set operating parameters to which the actual operating parameters of its actuator driving device correspond.
The present invention takes advantage of the fact that the address is assigned depending on the operating parameters of the actuator driving devices that occur when the actuator driving devices displace their respective assigned actuators from one end position to the other end position. The set parameters to be expected have been established with consideration to the given circumstances and the production tolerances and have been stored in the control device together with their assigned addresses. In an alternative variant of the invention, all set operating parameters to be expected are stored in each unit together with the respective assigned addresses.
Using the actual operating parameters resulting from the displacement of the actuators from the one end position to the other, each unit can be individualized by comparing the set operating parameters to the actual operating parameters and determining within which set operating parameters the actual operating parameters of the units fall. Thus, the control device can assign an address to each unit, or each unit assigns an address to himself.
The present invention becomes particularly transparent if the displacement path along which the actuator moved by an actuator driving device can be displaced, is defined as an operating parameter. If no other values are considered besides the displacement paths to define the operating parameters, a unique assignment of an address to a unitrequires that the displacement paths of the units are different. In this case, also the ranges of the displacement paths (set operating parameters) must be different which, as is assumed in the present case, are stored in the control device together with the addresses assigned to them. In response to a central command from the control device, the actuators of all units are moved to the one end position. Upon another central command from the control device, all actuators are moved to the other end position. In the process, the units determine the actual displacement. This may be done, for example, by a revertive potentiometer as is the case, for example, in an actuator driving device with position control, or by counting the steps of a stepper motor. In any case, the actual displacement paths are stored in the units after displacement of their actuators from the one end position to the other end position.
Then, the control device issues data word pairs. These data word pairs consist of data, on the one hand, representing the set displacement path ranges of the individual actuators in consideration of potential tolerances, and of address data, on the other hand. The individual units now check in which of the set displacement path regions the previously determined actual displacement path ranges of their actuators fall. They accept those address data that are assigned to the set displacement path ranges within which the actual displacement paths of their actuators lie. In this manner, each unit is accorded a unique address.
The above described method of using the displacement paths of the individual actuators as operating parameters is applicable whenever the displacement paths of the actuators of bus system units differ sufficiently, even in consideration of tolerances, so that a unique assignment of addresses to units can be made on the basis of the actual displacement paths. However, bus systems exist, where the actuators of two or more units have the same or substantially the same displacement paths. Exemplary for such bus systems are the actuator driving devices of the air distributing flaps and the heating and cooling fluid of a heat and cold exchanger in a vehicle air condition, where different set temperatures may be set by the driver and the co-driver (so-called left/right air conditioning systems). These systems may have a xe2x80x9csymmetricalxe2x80x9d design where each component is provided twice, i.e. once for the driver and once for the co-driver. In such a bus system, there are always two units whose actuators can travel the same displacement path between their respective end positions (in consideration of production and assembly tolerances, of course).
A first possibility to have addresses assigned according to the present method also in such systems is to make the pairs of equal displacement paths different by structural means. This is possible without the two subsystems reacting or operating such that the passengers of the vehicle could sense the difference.
Another possibility is to use different operating voltage polarization for the units of each unit pair having actuator driving devices with actuators having the same displacement path. The operating voltage is a DC voltage so that the different polarization would cause the actuators to be displaced in opposite directions if those units are controlled in the same way. By connecting a diode full bridge between the DC power supply and the actuator driving devices, the operating voltage at the actuator driving devices has the same polarization for all actuator driving devices. By tapping one of the input terminals of the diode full bridge, the polarization of the unit with the DC power supply can be detected. Besides the data for the set displacement path ranges, the kind of polarization is further stored as a set operating parameter. Address data are assigned to these data sets so that, despite identical displacement paths, a difference can be made between two units or two actuator driving devices having the same displacement path, thereby again obtaining a unique address assignment.
Besides the length of the displacement paths and/or the polarization of the actuator driving devices with the DC power supply, the operating parameters can additionally and/or alternatively also represent the size and/or the course in time of the currents flowing through the actuator driving devices during the displacement from the one end position to the other. In particular the variation of the current with time upon reaching the end positions may be employed to create a distinction between the two units of each pair in a system where pairs of the actuators of each unit have almost identical displacement paths. This is possible in particular with a xe2x80x9csymmetricallyxe2x80x9d arranged system with actuators adjusting flaps such as in a vehicle air condition system where the temperature may be set individually on the driver""s and the co-driver""s side. The air distributing and temperature mixing flaps of such a system are provided with a sealing to close substantially tightly in one end position (CLOSED position). The stop is relatively xe2x80x9csoftxe2x80x9d in this end position, whereas the other stop is xe2x80x9charderxe2x80x9d. When the two mutually symmetrical flaps that are displaced by the actuator driving devices of the two units in a pair are moved from the one end position to the other, the current flow for one flap is different from that of the other flap near the end of the displacement path, while the displacement path is substantially the same. When assigning addresses at a later time, this can be used to make a distinction between the two units whose two flaps have substantially the same displacement path.
Similarly, the magnitude of the current can be employed to distinct between two units whose actuators travel substantially the same displacement path. This is used, for example, in all cases where the actuator is biased by mechanical spring force towards the one of the two end positions. When being moved from the one to the other end position, one of the two symmetrically arranged flaps acts against the spring force, whereas the movement of the other flap is supported by the spring force.
The previously described possibilities of making a distinction between two units of a bus system by the amount of current consumption and the variation of the current with time can be used wherever the mechanical connection between an actuator and the actuator driving device assigned thereto is symmetrical. With respect to the actuators, the actuator driving devices are on different sides of the actuators. As long as this is given, such as in the air supply channel system of a left/right air condition system of a vehicle, there are possibilities to make a distinction between the units despite the pairs of substantially equal displacement paths of the actuators, namely, by using the operating parameters. This is different, however, for pairs of alternate polarization of the actuator driving devices of the units of a bus system. Here, a xe2x80x9csymmetricalxe2x80x9d design of the coupling between the actuator driving devices and the actuators is not necessary.